Natural convection heat transfer of nanofluids along a vertical plate embedded in porous medium

Heat transfer analysis of buoyancy opposing radiated flow of alumina nanoparticles scattered in water-based fluid past a vertical cylinder

Cooling and heating are two critical processes in the transportation and manufacturing industries. Fluid solutions containing metal nanoparticles have higher thermal conductivity than conventional fluids, allowing for more effective cooling. Thus, the current paper is a comparative exploration of the time-independent buoyancy opposing and heat transfer flow of alumina nanoparticles scattered in water as a regular fluid induced via a vertical cylinder with mutual effect of stagnation-point and radiation. Based on some reasonable assumptions, the model of nonlinear equations is developed and then tackled numerically employing the built-in bvp4c MATLAB solver. The impacts of assorted control parameters on gradients are investigated. The outcomes divulge that the aspect of friction factor and heat transport upsurge by incorporating alumina nanoparticles. The involvement of the radiation parameter shows an increasing tendency in the heat transfer rate, resulting in an enhancement in thermal flow efficacy. In addition, the temperature distribution uplifts due to radiation and curvature parameters. It is discerned that the branch of dual outcomes exists in the opposing flow case. Moreover, for higher values of the nanoparticle volume fraction, the reduced shear stress and the reduced heat transfer rate increased respectively by almost 1.30% and 0.0031% for the solution of the first branch, while nearly 1.24%, and 3.13% for the lower branch solution.

A numerical study of chemical reaction in a nanofluid flow due to rotating disk in the presence of magnetic field

In this paper, a numerical study of MHD steady flow due to a rotating disk with mixed convection, Darcy Forchheimer's porous media, thermal radiation, and heat generation/absorption effects are explored. A strong magnetic field is applied in perpendicular direction to the flow which governs the Hall current effects. Homogeneous and heterogeneous reactions are also taken into account. For the simplification of partial differential equations (PDEs) into the nonlinear ordinary differential equations (ODEs), the method of generalized Von Karman similarity transformations is employed, and the resulting non-dimensional ordinary differential equations are solved by using the homotopy analysis method (HAM). Effects of different parameters on the axial, radial and tangential velocity profiles, temperature and concentration of chemical reaction profiles are analyzed and discussed. The present work's remarkable finding is that with the expansion of nanoparticles size, dimensionless constant parameter, local Grashof number, porosity parameter, Hall current, and suction parameter, the nanofluid radial velocity is enhanced. For the higher values of magnetic field parameter, the tangential velocity and nanofluid temperature are enhanced. The magnetic field parameter and the disk thickness coefficient parameter have similar impacts on the axial velocity profile. Heterogeneous chemical reaction parameter decreases the concentration of chemical reaction profile. The nanoparticles volume fraction increases the concentration of chemical reaction profile. Furthermore, the present results are found to be in excellent agreement with previously published work in tabulated form.

Experimental Research on Stability and Natural Convection of TiO2-Water Nanofluid in Enclosures with Different Rotation Angles

The stability and natural convection heat transfer characteristics of TiO₂-water nanofluid in enclosures with different rotation angles (α = -45°, α = 0°, α = 45°, and α = 90°) are experimentally investigated. The effects of different pH values and doses (m) of dispersant agent on the stability of TiO₂-water nanofluid are investigated. It is found that TiO₂-water nanofluid with m = 6 wt% and pH = 8 has the lowest transmittance and has the best stability. The effects of different rotation angles (α = -45°, α = 0°, α = 45°, and α = 90°), nanoparticle mass fractions (wt% = 0.1%, wt% = 0.3%, and wt% = 0.5%) and heating powers (Q = 1 W, Q = 5 W, Q = 10 W, Q = 15 W, and Q = 20 W) on the natural convection heat transfer characteristics are also studied. It is found that the enclosure with rotation angle α = 0° has the highest Nusselt number, followed by the enclosure with rotation angles α = 45° and α = 90°, the enclosure with rotation angle α = -45° has the lowest Nusselt number. It is also found that natural convection heat transfer performance increases with the nanoparticle mass fraction and heating power, but the enhancement ratio decreases with the heating power.

The Effect of Radiation on Free Convection from a Heated Horizontal Circular Cylinder

Effect of radiation on free convection on heated horizontal circular has been investigated. The cylinder is fixed and immersed in a stationary fluid, in which the temperature is uniformly heated about the temperature of the surrounding fluid. The governing equation are transformed into dimensionless non-linear of partial differential equations and solved numerically by employing a finite difference method. An implicit finite difference scheme of Crank Nicolson method is used to analyze the results. This study determine the effects of radiation parameter, heat generation parameter, and the Prandtl number, , on the temperature and velocity profiles. The results of the local heat transfer and skin-friction coefficient in the presence of radiation for some selected values of Prandtl number and heat generation parameter have shown graphically.Keywords: Radiation; free convection; heated circular cylinder; heat generation.